Oil burner



O. J. APPEL Aug. 3, 1937.

OIL BURNER Filed June 14, 1952 2 Sheets-Sheet l Y INVENTOR car J )ATI'QRNEW 7 0. J. APPEL Aug. 3; 1937.

OIL BURNER Filed June 14, 1932 2 Sheets-Sheet 2 ATTORNEYS Patented Aug. 3, 1937 UNETED STATES PATENT OFFICE Oscar J. Appel, Paterson, N. J.

Application June 14, 1932, Serial No. 617,086

12 Claims.

This invention relates to oil burning apparatus and aims to provide certain improvements therein.

The invention is directed to those types of oil burning apparatus used for household or other heating, wherein there is a burner mechanism, usually centrally arranged, which has means for discharging oil in the form of a spray outwardly toward the sides of the furnace. Usually this spraying mechanism comprises a rotary member from which the oil is discharged tangentially by centrifugal force, and associated with this rotary member is usually a fan of the centrifugal type which discharges air in the same general direction as the oil spray.

It is customary in this type of heating apparatus to use a horizontal partition between the spraying apparatus and the inner wall of the furnace to which the apparatus is applied. 'This partition, which is customarily called the hearth, may be of cement or other fireproofing material, and closes off the space between the burner wall (usually at the water leg of the latter) and the outer casing of the spraying apparatus, 5 so that no air will pass upwardly through the ash pit of the furnace except that which is permitted to pass, by the construction of the burner parts.

It has been found in practice that much better results are secured in this type of furnace if 30 the air and oil are not sprayed directly upon the furnace wall, since this wall, being cooled by the water in the boiler, is not conducive to combustion. On the contrary, it has been customary to provide a refractory ring which is sepa-' 35 rated from the boiler wall and is, hence, not cooled by the latter, which refractory ring, in the operation of the burner, soon reaches a high temperature and thus raises the temperature of the sprayed oil to such degree as to transform it 40 into more or less gaseous form and permits a proper intermixture of the air discharged from the fan, so as to produce a more nearly complete combustion. Such refractory rings, which may be made in a single unit, or, as isrnore usual, of a 45 number of sections, are customarily provided with a base or horizontal portion which rests upon the hearth, and a vertical portion against which'the oil is sprayed. Being located near the wall of the furnace, certain types of this apparatus have :50 been called wall flame burners,it being an objective to concentrate the flame initially produced by the oil at points near the wall of the furnace and, to prevent the flames traveling back toward the spraying apparatus. This is for the two-fold 55 reason of preventing the burner parts from over heating and for preventing combustion until the proper fuel mixing process has been completed.

According to the present invention, I provide a construction having Various features of improvement over the constructions heretofore known. 5 In the preferred form of the invention I provide means for inducing a thorough mixture of the air and oil spray at a point in front of the vertical refractory wall, that is to say, between the vertical refractory wall and the oil-spraying appa- 10 ratus. This I prefer to effect by inducing a turbulent action of the air and oil just in. advance of the refractory wall. In the preferred form of the invention I also introduce means for burning the larger part of the fuel at the rear of the re- 15 fractory wall. To secure this effect I construct this .wall with numerous passages or apertures, thereby permitting the combustible mixture to pass to the rear of the wall, the latter acting as a mixing device for the fuel and air and preheating it to a considerable extent. I

Preferably, also, I, provide a construction in which the vertical refractory wall is a separate member formed of one of more sections, which member is arranged in substantially ring form and rests upon or is supported by the hearth. In those constructions wherein the means for securing the turbulent action referred to are formed on a separate base member, the separate refractory wall may conveniently rest upon this base member. In this case the base member may be formed of less expensive refractory material than the vertical wall. This construction permits a cheaper assembly than would be the case if expensive refractory material were used throughout, and it also materially assists in setting up the parts and replacing any particular part of the vertical wall if the latter should become deteriorated or injured. In the best construction of my invention such a base member is used, and it is also provided with a vertical flange lying back of and spaced from the vertical refractory wall. According to this construction there is provided an ignition area, a normal flame area in the form of a ring lying at the front of the vertical refrac tory wall and a main flaming space at the rear thereof.

Referring to the accompanying drawings, which illustrate several forms of the invention;

Figurel isa horizontal section of a common type of boiler showing a plan of the hearth, the rotary burner e1ement,and in detail a section of a part of the refractory wall. This figure 111115: trates' 'a round refractory assembly as used in a and preferably is formed with a foot portion K on which it may rest securely when merelyf being shown in section.

Figure 2 is a view partly in section and partly in perspective, showing a refractory assembly of 'fractory wall. a

Figure 6 is a detail perspective showing a different arrangement of perforations through the vertical refractory 'wall.

Figure 7 is a detail sectional view of. another modification of vertical refractory wall.

Referring first to Figures 1, 3 and 4, letA indicate the water leg of a suitable steam boiler having an inner wall B. C represents a rotary burner of the customary typehaving an outer casing. D (Fig. 4). and the inner wall B of the boiler is usually a horizontal partition or hearth E, customarily made of cement, and usually intercepting the flow of air fromithe ash pitupward except that which is thrown outward by the burner. The burner is provided with some form of spraying A nozzle or nozzles, such for instance as. is shown in Fig. 4 at F, and a series of blades, one of which may betaken as indicated at G in Figure 4, the nozzle and blade beingadapted to be rotated at a reasonably high rate of speed by a suitable motor arranged beneath the hearth, and

. not illustrated.

As the burner is rotated, a spray of finely divided oil is thrown off tangentially at the desired level, and also air is tangentially discharged from the fan blades, this occurring at all parts .of the circumference of the burner. assembly.

There is thus formed horizontal sheets of oil spray and air thrown off rapidly toward the inner wall of the furnace. 'These sheets of oil 1 and air are intercepted by the vertical refractory wall'H provided by my invention. Preferably,

this'wall rests 'upon a refractoryor semi-refractory base I, which. may be formed of cast iron or any other suitable material, which base, preferably, also has on its outer side a vertical flange J formed integrally withthe base and constituting with the latter a substantially continuous ring of circular form, such as is shown in Figure 1, or of any other suitable conformation, such, for instance, as the substantially square ring shown in Figure 2;

o the resent nvention, the refrac- Accordmgt p 'ferred form, the main combustion zoneis not located at the inner side of the refractory wall H. It will be observed that throughout thiswall tory wall H is made separate from the base I,

V placed on top of the basewithout any necessity for cement or other fastening means. The wall H, which is subjected tohi'gher temperatures refractory. than the. ring. The refractorywall H may be made as a complete ring, or, as is preferabie', it may be formed of aconsiderable number of, sections such-as are illustrated, for instance, in Figures 1, 2, and6. This permits very easy and cheap replacement incaseof necessity.

V in frontof the refractory wall H a-m'eans for h producing a considerable degree of turbulence or f According to my invention, I prefer to provide Between this outer casing latter.

generally square boiler, the water leg of the latter refractory wall. 7 use for this purpose are best illustrated in Figure strong eddying a short distance in front of the V The means which I prefer to 3, and comprise a'series of vanes, ribs or baffles L, which may be conveniently formed as part 'of the base I, andwhich may be considered as directing baffles or vanes, intended to break up the sheet of oil spray and air and assist in caus- 7 ing a thorough intermixture of the two prior to 7 l0 baffles L in oblique position, the direction of ignition. To this end, I preferably arrange the obliquity being contrary to the normal direction of travel of the particles of oil and draft of air discharged by the burner. It is understood that these particles are discharged tangentially,

and not radially, and consequently, if permitted to reach the boilerwall, would strike .the latterat a more or less oblique angle, as is illustrated by the arrows M,1M, in Figure 1. The direction of the ribs or baffles L is such that they intercept a portion of the sheet of oil and'air' and cause a violent change indirection of the latter, thereby 'creating a'series of strong eddies which produce a high degree of turbulence not onlybehin'd the baffles L but above and around the same. This is very desirable, in that it insures a very thor-' burner and secures a cool condition of the latter,

which protects its structure and lengthens its life. It also tends ,to avoid the flaming of an unsuitable oil-gas mixture which would unnec-L essarily increase smoking of the burner.

By reference to Figures 1, 2, and '7, it will be observed that a suitable pilot light N is provided I for igniting the mixture in what I have described as the main ignition area which is comprised between the row of baffles Landthe refractory wall H, and which area is indicated by the reference letter O.

Withthe oil in the condition producedby the I thorough admixture providedfor, the ring or" flame in the'main ignition area ignited by the pilot keeps substantially constant. Since only a part of the combustible mixture strikes the bafiles, that. which passes over them strikes the refractory wall H, is ignited by the ring of flame in the main ignition area, and a certain amount of combustion continues along the inner face of the refractory wall If and up into the boiler passages. f

According to my invention, however, in itsprea I arrange apertures, such as are shown at P, for

instance, in Figures 1, 2, 3, and 4. "These'apertures extend through the wall H andare entirely surrounded by portions of therear ofthe wall,

thereby producing atthe rear of the wall pro 'tected 'low pressure areas on all sides of the apertures. A large amount of the gaseous mixa ture passes through'these apertures, both in the 5 ignited and unignited; condition, particularly the During such passage the gases are further heated by contact with the refractory wall,

and there is established behind the latter a main combustionzone Q. This combustion zone is in close juxtaposition to the inner wallB'of the furnace, and a considerable amount of flame is thrown against this wall so as to transfer its heat to the water in the water leg of the boiler. It will be understood that a certain part of the gaseous mixture, after it has impinged against the wall H, is ignited and thrown upwardly along the inside of the vertical wall, and to some extent over the top thereof, a part of it sweeping the upper portion of the water leg of the boiler and the other impinging against the crown sheet of the boiler. The arrows in Figure 4 show the general course of the gases and products of combustion.

Any suitable ignition means may be employed; the conventional form of gas pilot light shown at N in Figure 7 comprises, generally speaking, a tube S leading to a gas supply and having jet orifices T, the whole being covered by a hood U.

In the operation of the device shown in Figures l to 4, when the rotary burner C is set in operation oil and air are discharged tangentially therefrom in the form of a sheet or sheets, the oil being in a spray of comparatively large globules. The lower part of the air sheet strikes the ribs or bafiles L with considerable velocity and is abruptly deflected in an angular direction from its original flow while moving in substantially the same plane. Passing through the spaces between the bailles, the deflected air produces cross currents, which, acting upon theupper sheet of air, sets it into a state of turbulence or agitation which tends to break up the oil in much finer particles particularly the lower portion of the oil stratum and to produce a better combustible-mixture. Finally reaching the wall H, the air and finely atomized oil of the lower oil stratum strike against the wall, and by the impact the oil particles are further subdivided and the mixture then becomes a homogeneous one, suitable for burning purposes. Ignition takes place through the medium of a pilot, and a ring of flame is set up along the ignition area 0, which ignition area serves to ignite the main body of the oil above the lower portion of the oil stratum. This main body of oil reaches the vertical refractory wall H above the series of bafiles at considerable speed, and the impact of this oil striking the inside face of the wall causes said oil to become subdivided and broken up, thereby providing the formation of a thoroughly combustible mixture, which is very quickly improved by the fact that the refractory wall soon becomes highly heated, and the hot surface thus presented assists in bringing the combustible mixture to a finer degree of vaporg ization. At the start of the operation the turbulent mixing in the ignition area secures at this point a readily ignitible flame ring, which is sufficiently protected by the baffles to avoid being extinguished by the main body of the air and spray directed above the baifle series, for the rate of flame propagation of the mixture in the ignition area 0 is greater than the air velocities in the immediate vicinity. The pressure of the mixture and the chimney draft causes a considerable quantity of it to pass through the apertures P to the rear of the refractory wall.

It being usually true that that part of the mixture which passes through the lower series of apertures is in ignited form, this serves to insure an ignition of the unignited vapors which pass through the refractory wall H, and thus maintains between this wall and the wall of the combustion chamber an active heating flame. During the passage of the mixture; through the wall, particularly when the latter is. hot, there. is a.

further mixing of air and oil particles, and a heating of the mixture, which insures that the mixture shall be in readily ignitible form to support intense combustion in the combustion zone Q.

During the operation described the ribs or baffles L act to break up the force of the sheet of air in one direction by inducing the lower part of the sheet of air and a part of the partially mixed air and oil to divert their travel along other angles within the same plane causing a more intimate mixture, with the result that the inner ignition ring of flame suffers no liability of being extinguished. The complete ring of flame entering the apertures in the annular wall H is quickly formed at the start of the operation and continues uninterruptedly during the complete operation of the burner.

A similar action takes place behind the refractory wall H, for while the apertures in the wall permit the passage of considerable quantities of mixture, the ring of flame which is established at the lower part of the flaming space Q is sufficiently protected to maintain its integrity throughout the operation. A certain degree of turbulence is also observable at the rear of the refractory wall, because of the jet form of the mixture as it issues through the apertures in the Wall.

Any liquid oil which, particularly during the starting of the operation, strikes against the wall or passes through the same without substantial intermixture of air, passes down to the ignition area 0 in front of thewall or to the area Q behind the wall. Oil which may pass through the apertures and strike directly against the flange J of the ring I is led downwardly by this flange.

In Figure 5 I. have shown a modified form of refractory wall H in which the ribs or bafiles L are omitted. In this construction the wall is provided on its front face with a bead V. This bead acts to deflect downwardly a certain proportion of the mixture, and creates a certain amount of turbulence thereby, thus producing a combustible mixture which serves for the ignition space 0, and at the same time tends to reduce the normal upward drive along the wall above it, so that the ignition area 0 is to an extent protected so that the extinguishing of the ignition flame is not allowed to take place. In other respects, the action is similar to that of the form of the invention shown in Figures 1 to 4.

In Fig. 6 I have shown the refractory wall H as formed with vertically elongated openings P. In all other respects the construction and action of the hearth shown in said figure is similar to that of the form of the invention shown in Figs. 1 to 4.

In Figure 7 I produce a similar effect by giving the front face of the wall H (and preferably the rear face) a double curved form, a portion W extending inwardly toward the burner tending to protect the flaming area 0 An outward curve of the wall at X, followed by an inward curve at Y, also increases the tendency to check the violent sweep of the flames upwardly along the inside face of the wall.

The invention as thus described secures the proper shape, placement and colorof the flame, and produces a thorough combustion. A' great stability of the flame is secured, and ignition is very prompt and reliable.

Depending upon the character, size and multiplicity of. the. apertures in the refractory wall,

' understood that, irrespective of the point of ignition with regard to. whether it is at the front or at the rear of the wall, the products of combus:

tion merge to a considerable extent over the top of'the wall and pass to the .crown sheet-of the boiler.

While I have described a refractory 'wall as:

generally vertical, it will be understood that it may vary quite considerably from this position in either direction.

In many instances the flange J of the base ring I may be completely omitted, since the air and oil have been so broken up and vaporized by the time they pass through the refractory 'wall, that they are ideally combustible and may be permitted to sweep directly against the interior wall of the combustion chamber or water leg. Obviously, the invention is not dependent upon the particular shape of the apertures in' the wall, Figure 6 illustrating elongated slots instead of circular apertures. They may be formed in any suitable way.

Irrespective of the form of apertures selected for the refractory wall, it is important that they should at their rear be entirely surrounded by portions of, the wall so that the wall area facing rearwardly through which the combustible mixture passes produces an endless protected or low pressure area around each aperture, which materially helps to retain the flame within the main flaming area and in close proximity to the rear of the wall. It is also preferable that this wall should have a substantially unbroken top of considerable area. other refractory walls it has been found that a section or sometimes the whole ring of flame is apt to lift from the wall, or to refuse to burn at certain points whenever a downdraft or other adverse draft condition exists, ,or whenever a tendency for the air to blow away the flame occurs; The top wall provides an area which in connection with the up-draft tends to create avacuum or protected area immediately above the wall, so that there'is established a second ring of flame which provides for continuous ignition.

for the ,main flame area behind and above it.

Many other changesmay be made in the construction shown and described. without departing from the spirit of the invention.

I claim:

1. In a burner apparatus, the combinationof a centrifugal burner head. adapted to discharge. a horizontal spray of oil and a draft of air, an

upright wall for intercepting the oil spray and air draft surrounding said burner head, a hearth extending from theburner head to the wall below the level of the burner head, a series of spaced vanes between said wall and the burner head to receive a portion of the draft of air therebetween for producing a turbulent action of. the oil spray and air at the front of said'wall, said vanes being located below the oil spray from the burner head but in the path ofa portion of the draft of air 7 therefrom, and said wall having perforations leading to the rear'thereof..-

2. In a burner apparatus, a centrifugal burner head adapted to discharge a horizontal spray of oil and a draft of air, an upright refractory mixing wall for intercepting This is'due to the fact that with the combination of 7 the oil. spray and air draft surrounding said burner head, a hearth extending from the burner head to the wall below the level of'the burner head, and a series of vanes in front of said wall and spaced therefrom, acting to produce a turbulence in the oil spray and air issuing from said burner head, said vanes being disposed below the oil spray from the burner head and in the path of a portion of the draft of air.

3. In a burner apparatus the combination of a combustion chamber, a centrifugal burner head adapted to discharge a horizontal spray of'oil and a draft of air, a refractory wall for intercepting the oil spray and air draft surrounding said burner head, a hearth extending from the burner head to the wall below the level of the burner head, said refractory wall being spaced from the inner wallof the combustion chamber and having 'a series of perforations through which the fuel and air can be projected, and vanes in fixed position in front of said refractory wall low the oil spray from the burner head and spaced from the lower portion of said refractory wall to intercept and deflect a portion of the air draft and to provide an ignition space, and ignition 3 means within said space for igniting combustible gases within said space.

5. A burner apparatus comprising in combination acentrifugal burner head adapted to discharge a horizontal spray of oil and a draft of air, a refractory wall for intercepting the oil spray and air draft surrounding said burner head and a series of vanes arranged in front of said wall and spaced from the lower portion thereof to provide an ignition space, and ignition means within said space for igniting combustible gases within said space, said refractory wall having perforations leading to the rear thereof through which combustible gases can pass to produce a flame at the rear of said wall.

6. A burner apparatus comprising in combi- 7 nation a vertical centrifugal burner, head adapted to discharge outwardly an oil spray and an air draft, a hearth extending outwardly from the burner head below the level thereof, a base ring mounted on the hearth surrounding the burner. head, said base ring having at its outer periphery an imperforate vertical flange or wall for intercepting the oilspray and air draft, and a refractory wall located on said base ring and spaced inwardly from said flange, said refractory wall comprising a plurality of sections placed end to end,

and each section having a foot portion upon which it stands on said base ring.

'l. A burner apparatus comprising in combination a combustion chamber, a centrifugal burner head, a casing for said head, said burner head being adapted for discharging outwardly an oil spray and an air draft, a hearth extending outwardly 'from the casing to the wall of the combustion chamber, a base ring on. the hearth surrounding said burner head casing and having at its outer periphery a vertical flange and atits inner periphery a plurality of spaced vanes of lesser 7 height than the flange, and a refractory wall for intercepting the oil spray and air draft between said flange and said vanes.

8. A burner apparatus comprising a central centrifugal burner head adapted to discharge outwardly an oil spray and an air draft, a refractory oil impacting wall surrounding said burner head and spaced therefrom, a hearth extending from said burner head to said wall, said impacting wall comprising a series of sections each having a foot portion upon which it stands and each having groups of perforations extending therethrough from the front of said wall to the rear thereof, the lower portion of the front of said wall forming an initial impact surface for the oil spray from the burner head.

9. A burner apparatus comprising a central centrifugal burner head adapted to discharge outwardly an oil spray and an air draft, an upright perforated refractory wall for intercepting the oil spray and air draft surrounding said burner head in spaced relation thereto, a hearth extending from said burner head to said wall, and said wall having a corrugated front face, with the furrows and ridges of said corrugations running horizontally and extending circumferentially of the vertical face of said perforated wall, the perforations extending through said wall from the front face to the rear thereof.

10. A burner apparatus comprising a central centrifugal burner head adapted to discharge outwardly an oil spray and an air draft, an upright perforated refractory wall for intercepting the oil spray and air draft surrounding said burner head in spaced relation thereto, and a hearth extending from said burner head to said refractory wall, said refractory wall having a circumferential rib arranged on the front side of said wall and pro jecting inwardly therefrom and spaced above the lowest part of the wall but not above the lowest perforation therein.

11. In a burner apparatus, in combination, a centrifugal burner head adapted to horizontally discharge oil and air, an outer wall surrounding said burner head in horizontally spaced relation thereto, a hearth extending from the burner head to said wall, an apertured refractory wall spaced inwardly from said outer wall, a loaiiie of lesser height than the refractory wall spaced inwardly therefrom to provide an ignition space, the lower portion of the inner face of said apertured wall forming an initial impact surface for oil discharged from the burner head, and. means for igniting the combustible mixture in said ignition space, said refractory wall having a top of considerable unbroken area for retaining a ring of protected flame adapted to maintain ignition of the combustible mixture within and above the ignition space.

12. A burner apparatus comprising, in combination, a centrifugal burner head adapted to horizontally discharge a spray of oil and a draft of air, a refractory wall for intercepting the oil spray and air draft surrounding said burner head in spaced relation thereto, and a series of vanes arranged in front of said Wall in the path of the air discharge to produce a turbulent mixture of oil spray and air issuing from said burner head at the refractory wall, said series of vanes being spaced from the lower portion of said re fractory wail to provide an ignition space, and said vanes being arranged to point outwardly away from the direction of rotation of said centrifugal burner head toward said wall so as to deflect air impinging thereon in a direction contrary to the normal direction of travel of said air.

OSCAR J. APPEL. 

